Bariatric Surgery Ameliorates Diabetic Cardiac Dysfunction by Inhibiting ER Stress in a Diabetic Rat Model

Cardiac dysfunction is a severe complication of diabetes, with no effective treatment. Currently, bariatric surgery is more and more widely used to attenuate diabetes-associated diseases. The mechanism is not clear. Endoplasmic reticulum (ER) stress-dependent apoptosis has been observed in the progression of diabetic myocardium damage. Therefore, this research was designed to investigate the effects of different bariatric procedures on cardiac dysfunction via ER stress-induced cardiomyocyte apoptosis pathway in a diabetic rat model.

Duodenal-jejunal bypass (DJB), sleeve gastrectomy (SG), and sham surgery were performed in diabetic rats. Echocardiographic examination, H&E staining, Masson staining, and TUNEL staining were performed to measure the diabetes-caused heart damages. ER stress-associated signaling molecules like glucose-regulated protein 78 (GRP78), protein kinase RNA (PKR)-like ER protein kinase (PERK), p-PERK, inositol-requiring enzyme 1ɑ (IRE1ɑ), p-IRE1ɑ, activating transcription factor 6 (ATF6), C/EBP homologous protein (CHOP), and caspase 12 were measured and compared among DJB group, SG group, and sham group.

Compared with sham group, DJB and SG groups both had significantly lower GRP78, PERK, p-PERK, CHOP, and caspase 12, though there was no statistical change on IRE1ɑ, p-IRE1ɑ, and ATF6. DJB and SG groups also showed improved heart function and lower cardiomyocyte apoptosis in diabetic rats.

DJB and SG ameliorated cardiac dysfunction by inhibiting PERK-mediated pathway. And no difference was observed on the effects of DJB and SG on ER stress-dependent myocardium damage in diabetic rats.